The present invention is generally directed to staged water purification devices in which, during the first stage of purification, potable water passes through a filter for removing particulates and chemicals prior to the water passing on to the second stage in which the water is exposed to ultraviolet light for the killing and sterilization of bacteria and other microorganisms. More particularly, the present invention is directed to a unique baffle and deflector combination provided within an ultraviolet light treatment chamber for control of the flow pattern of water as it passes through the treatment chamber and is exposed to the ultraviolet light source.
Staged water purification devices which are used to purify potable water by passing the water through an ultraviolet light vessel subsequent to passing the water through a filter during a prior stage are known in the art. In designing such devices, it is desirable that during operation of such a device to provide exposure of as much of the water as possible to a source of ultraviolet light while maintaining a continuous, uniform flow of water through the device and adequate water pressure at the spigot. It is also desirable to control exposure time or residency of the water to the ultraviolet light source within the vessel in order to achieve optical kill rates of microorganisms.
Some prior artisans have attempted to achieve such optical results by designing a generally cylindrical ultraviolet water treatment vessel having a water inlet passage on one end of the vessel, a coaxially disposed ultraviolet light tube extending the length of the vessel and a water outlet passage disposed on the end opposite the inlet passage downstream from a filter. In such an ultraviolet water treatment vessel the ultraviolet light bulb in combination with the inside walls of the treatment vessel define a space, parallel to the sides of the cylindrical vessel, through which the water circuits for the inlet passage through the outlet passage wherein the water is exposed to the ultraviolet light radiating from the ultraviolet light bulb before passing on to a filter for further purification.
In such systems, the inlet passage is typically comprised of a tube which is small in diameter relative to the diameter of the cylindrical treatment vessel. One problem that is caused by water entering a relatively large chamber from a relatively small inlet passage tube is that some water typically would short-circuit through the chamber past the ultraviolet light bulb and out the outlet passage without receiving sufficient exposure to ultraviolet light to kill all microorganisms present while another portion of the water will linger in the treatment vessel in the form of small eddy currents creating dead spots. The combination of eddy currents and short-circuiting water results in the undesirable effect of having a portion of the water receiving insufficient exposure time to the ultraviolet light thereby compromising its effectiveness.
Other artisans have attempted to control the flow of water past an ultraviolet light source by passing the water through a helical conduit manufactured of ultraviolet light permeable material and coaxially disposing an ultraviolet light source through the center of the helix. While channeling the water through a helical conduit around an ultraviolet light source is effective in eliminating short-circuits and dead spots in the water path, such conduits have been known to be made of quartz or glass which can shatter and are difficult and costly to manufacture. Depending upon the purity of the quartz or glass, ultraviolet light will solarize impurities in the quartz or glass causing portions of the material to darken thereby compromising its transmission qualities for the transference of ultraviolet light.
In addition to maintaining the rate and pattern of flow of water through the ultraviolet treatment vessel, it is desirable in such water treatment systems to provide easy access to the ultraviolet light element by the user for replacement and inspection. Some prior artisans have provided a user removable housing cover for visually inspecting the wiring and other electric connections to the ultraviolet light element, yet have not provided an easy and safe way in which to remove the light element without first removing and disconnecting a complex array of electrical connections and/or structural components which mount and support the light element within the water treatment system vessel. Thus, it is highly desirable to provide a substantially self-contained ultraviolet light element which requires a minimum of disassembly by the user in order to access and/or remove the element from the water treatment system vessel.